This invention relates to a process for scouring and dyeing synthetic fibers in one-bath.
Synthetic fibers have been usually scoured by means of a continuous or batch scouring machine for the removal of oils and sizing agents adhered thereto prior to the dyeing. However, it has been recently needed to economize energy and save labor in many industrial fields. In the case of dyeing synthetic fibers, it has been much desired to scour and dye the fibers simultaneously in one-bath.
As to knitted fabrics of synthetic fibers, a process for scouring and dyeing in one-bath, though it is somewhat unsatisfactory, has been already applied, because the fabrics, in general, comprise only oils adhered thereto and the oils can be substantially removed by using an adequate surface active agent.
However, as to woven fabrics, a great amount of sizing agents of polyvinyl alcohol, polyester or polyacrylic ester which are adhered to the fabrics must be removed together with oils. There have been made many studies of removal of such sizing agents by using surface active agents. But satisfactory results have not been obtained. For scouring the woven fabrics, singular use of a surface active agent is scarcely effective, and an alkalizing agent is necessitated. On the other hand, for dyeing synthetic fibers with acid or disperse dyes, the dye bath must be made acidic so that the stability and good adsorption of the dyes can be achieved.
As described above, a bath when used for scouring must be made alkaline while one for dyeing must be adjusted to be acidic, which has prevented the synthetic fibers from being scoured and dyed simultaneously in one-bath.
It is, therefore, the primary object of this invention to provide a process for scouring and dyeing synthetic fiber fabrics simultaneously in one-bath, which is able to adjust the pH value of the one-bath to be within the ranges suitable for scouring and dyeing.